Production op molded articles



OFFICE.

THOMAS A. EDISON, OF WEST ORANGE, NEW JERSEY, ASSIG-NOR TO NEW JERSEY PATENT COMPANY, OF WEST ORANGE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

PRODUCTION OF MOLDED ARTICLES.

1,337,193, Specification of Letters Patent. No Drawing.

molded articles, especially phonograph rec- .ord blanks, and more particularly to an improved material or composition for such molded articles, an improved binder for said material and the processes of making the same.

The principal object of the invention resides in the production of a comparativel cheap material for molded articles which is of superior quality so that when formed into a molded article under heat and pressure, it will be hard, tough, substantially non-crystalline, very smooth and of sub-.

stantially uniform density and texture throughout.

In carrying out my invention, I first make the binder for the material to be molded by oxidizing any of a number of different resins, but preferably ordinary pine rosin. In oxidizing the resin, the same is preferably boiled for a considerable period with an oxidizing agent, such, for example, as peroxid of lead, the amount ofiperoxid of lead preferably being from 2%% to 6% by weight of the-resin. {The resin so oxidized constitutes a binder of superior quality inthe form of astifi' liquid which is neither too sticky nor too brittle when hardened.

The binder produced as described above is then mixed with a filler material. compris ing any suitable finely divided inert substance, such as china cla and a small quantity of fibrous materia, preferably cotton fflock, in a mixer which is heated to about 325 degrees Eghe mixer being operated until the ingredi ts are thoroughly mixed. When china clay and cotton flock are used for the filler of in improved material, ,I find that good resu ts are obtained by using from 20% to 25% by weight of theoxidized resin binder, about 3% by weight of cotton flock, and from 72% to,77% by weight 'of china cla Under some circumstances, however, I find -it desirable to increase the amount .-of'cotton flock to as much as 10% or' 12% Application filed January 23, 1919. Serial No. 272,773.

china clay. Hence I do not wish to be lim-.

ited to the proportions just stated."

The material is now removed from the mixer, cooled, and. then ground fine in a ball or pebble mill. During the grinding of the material, it is subjected to a stream of hot air in order to still further oxidize the resin binder. The material is subjected to the action of the current of hot air until the proper degree of oxidization is attained. Instead of oxidizing the material during the grinding thereof, it may be oxidized after being ground, by removing the same from the grinding mill and putting it into a revolving cylinder through which hot air is forced. After being ground, the material is ready for molding. In making disk record blanks, the powdered material produced by the ball or dpebble mill is placed in suitable molds a'n formed under hydraulic pressure and heat into disks. thus produced are very smooth and the disks are hard and tough and of substantially uniform density, being entirely free of hard spots such as are sometimes present in disk record blanks of a similar character heretofore produced.

Disk record blanks formed as described above may be covered with a suitable veneer or coating designed to be impressed with a sound record matrix, such as'the varnish consisting of "a. mixture of phenol resin and painting the same onto the blank. After the varnish has dried, the sound record 1s impressed therein under great heat and pressure in asuitable-mold provided with a sound record matrix. Blanks formed of my The surfaces of the disks improved material including the oxidized I res1n binder, will not flow to any great extent during the imprinting of the sound record in this manner. Sound records thus produced will be free from run outs due I tothe absence of hard spots in the blanks formed of my improved material. 'Moreover, such records, when reproduced, are substantially free from ',scratch. lhis I believe'is due tothe fact that a blank formed of my improved material is substantially perfectly smooth, with none of the fibers or particles of the filler projecting from the body of the blank, with the result that when the sound record is impressed into the varnish. coating, none of the particles of the fibrous or other material of the blank will be forced through the varnish coating or any appreciable distance thereinto so as to form irregularities in the surface of the record grooves.

While my improved material is especially designed for use in making sound record blanks, the same is adapted for use in making numerous other molded articles. Moreover,-it isto be understood that I am not limited to'the use of the particular ingredients described in forming my improved material, nor. to the exact method described hereinv for making such material, but that my invention is subject to various changes and modifications without departure from the spirit thereof or the scope of the appended claims.

Having now described my invention,-what I claim as new and desire to protect by Letters Patent is as follows: 1. A composition adapted for use in forming molded articles, comprising a finely divided filler material held together by a binder comprising an oxidized resin, substantially as descr bed. 1

2. A composition adapted for use in forming molded, articles, comprising a mixture of finely divided material and fibrous material as a filler, held together by a binder comprising as described.

3. A composition adapted for use in forming molded articles, comprising finely divided filler material held together by a binder consisting of oxidized rosin, substantially as described. 7

4. A binder adapted for material from which the molded articles are formed, the

binding agent of which consistsof an oxidized resin, only substantially as described.

5. A binder adapted for material from which molded articles are formed, the bind ing of which consists of oxidized rosin only,

substantially as described.

6. A composition adapted for use in forming molded articles, comprising a mixture of finely divided material and cotton flock as a filler, held together by a binder comprising an oxidized resin, substantially as described.

-7. 'A composition adapted for use in forming molded articles, comprising a mixture of powdered china clay and fibrous material as a filler, held together by a binder comprising -an oxidized resin, substantially as described. V

w 8. ,A composition adapted for use in forming molded articles, comprising a mixture ofp'owdered china clay and cotton flock as a filler held together by a binder comprisin w an oxidized resin, substantially as describe Y 9.. The method of producing material adapted for use in making molded articles, which consists in oxidizing aresin, and thenan oxidized resin, substantially.

the oxidized resin with a finely divided filler material, grinding the mixture and subjecting the same to an oxidizing action, substantially as described.

12. The method of producing material adapted for use in making molded articles, which consists in oxidizinga resin, mixin the oxidized resin with a finely divided fille material, grinding the mixture, and subjecting the same to a current of hot air, substantially as described.

13. The method of producing material adapted for use in making molded articles, which consists in boiling a mixture of a resin and an oxidizing agent, then mixing the resulting product with a finely divided filler material and fibrous material with the application of heat, cooling the mixture, and then grinding the mixture and subjecting the same to an oxidizing action, substantially as described. v

14. A-sound record blank formed from a composition comprising finely divided filler material held together by a binder comprising an oxidized resin, substantially as described. i

15. A sound record blank formed from a composition comprising finely divided filler material held togther by a binder comprising oxidized rosin, substantially as described.

16. A sound record blank formed of a composition comprising finely divided material containing fibrous material as a filler, held together by a. binder comprising an oxidized resin, substantially as described.

17 A sound record blank formed of a compositioncomp'rising finely divided ma terial containingcotton flock as a filler, held together by a binder comprising an oxidized resin, substantially as described. 7

' 18. A sound record blank formed of a composition comprising a mixture of 'pow-' dered china clay and fibrous materlal as a filler, held togther by a binder comprisin an oxidized resin, substantially as describe 19. A sound record blank formed of a composition comprising a -mixture of powdered china cla and cotton flock'a-s a filler, held together y a binder comprising an oxidized resin, substantially as described. This specification signedthis-15th day of January, 1919.

p'rHos. A. EDISON, 

